Method of making a flexible absorbent article with formed moisture barrier

ABSTRACT

An absorbent article includes a moisture barrier formed of a formable, liquid impermeable material. The moisture barrier defines a basin having a width dimension, a length dimension greater than the width dimension, and a volume. The basin includes a floor having corrugations formed therein parallel to the width dimension. The absorbent article also includes an absorbent assembly disposed within the basin and a liner formed of a liquid permeable material bonded to the moisture barrier and sandwiching the absorbent assembly therebetween. The corrugations permit the absorbent article to bend inwardly, for example to conform to the shape of the wearer, without bunching the moisture barrier along the portions facing the wearer and without substantially stretching or deforming the floor of the moisture barrier.

This is a divisional application of application U.S. Ser. No.08/292,561, filed on Aug. 18, 1994, now U.S. Pat. No. 5,607,415 issuedMar. 4, 1997.

BACKGROUND OF THE INVENTION

The present invention is directed to a flexible absorbent article forcontaining and absorbing bodily discharges. More particularly, theinvention pertains to a disposable absorbent article having a formedmoisture barrier that is adapted to fit comfortably against the body ofthe wearer.

Disposable absorbent articles contain and absorb urine and other bodyexudates, and have been designed for people of all ages. Most absorbentarticles have several common components, such as a liquid perviousbodyside liner, a liquid impervious moisture barrier, an absorbentmaterial disposed between the bodyside liner and the moisture barrier,and some form of attachment system for securing the product about thebody of the wearer.

In some instances, particularly adult incontinence products, themoisture barrier consists of a formable material that retains athree-dimensional shape. The formable material can be set in thethree-dimensional shape by manufacturing processes such asthermoforming, vacuum forming, injection molding or mechanical forming.Formable materials processed by these techniques provide a certaindegree of rigidity, which beneficially functions to maintain the shapeof the moisture barrier during use and allow the absorbent article tofill to its capacity.

One drawback of formed moisture barriers, however, stems from thisability to retain a three-dimensional shape. Formed, three-dimensionalmoisture barriers do not readily conform to the shape of the wearer, afactor which can impact comfort and absorbency. To improve the bodyconformity of formed moisture barriers, manufacturers have produced suchmaterials with a predetermined longitudinally curved shape. While thisaddresses the needs of some consumers, it does not entirely remedy theproblem due to the variety of shapes of wearers. Further, formedproducts with a predetermined curved shaped present particularlychallenging manufacturing hurdles.

Therefore, what is lacking and needed in the art is an improvedabsorbent article with a formed moisture barrier that is adapted toconform to the shape of the wearer.

SUMMARY OF THE INVENTION

In response to the discussed deficiencies in the prior art, a newdisposable absorbent article has been developed. The absorbent articleemploys a formed moisture barrier that generally retains its shapeduring use and is also easily bendable so that the article can conformto the shape of the wearer.

In one aspect, the invention pertains to an absorbent article includinga moisture barrier formed of a formable, liquid impermeable material.The moisture barrier defines a basin having a width dimension, a lengthdimension greater than the width dimension, and a volume. The basinincludes a floor having corrugations formed in the floor parallel to thewidth dimension. An absorbent assembly of the absorbent article isdisposed within the basin, and a liner formed of a liquid permeablematerial is bonded to the moisture barrier to sandwich the absorbentassembly therebetween.

In another aspect, the invention pertains to an absorbent articleadapted for attachment to clothing. The absorbent article includes amoisture barrier formed of a formable, liquid impermeable material anddefining a basin having a width dimension, a length dimension greaterthan the width dimension, and a volume. The basin includes a floor and aperipheral wall surrounding the floor, where the floor has first andsecond longitudinally spaced end regions and an extendable regionbetween the end regions. The extendable region includes from about 2 toabout 100 corrugations formed therein parallel to the width dimension.The absorbent article also includes means for attaching the moisturebarrier to clothing, which means include an adhesive disposed on thefloor solely in the end regions. An absorbent assembly of the absorbentarticle is disposed within the basin, and a liner formed of a liquidpermeable material is bonded to the moisture barrier to sandwich theabsorbent assembly therebetween.

In still another aspect, the invention pertains to an absorbent articlewith a moisture barrier formed of a formable, liquid impermeablematerial. The moisture barrier defines a basin having a width dimension,a length dimension greater than the width dimension, and a volume. Thebasin includes a floor having first and second longitudinally spaced endregions and an extendable region between the end regions, where theextendable region includes corrugations formed in the floor parallel tothe width dimension. The floor includes rib means which extend parallelto the width dimension for providing enhanced resistance to transversecompression of the moisture barrier. The absorbent article also includesan absorbent assembly disposed within the basin, and a liner formed of aliquid permeable material bonded to the moisture barrier to sandwich theabsorbent assembly therebetween.

Yet another aspect of the invention relates to a method of making anabsorbent article. The method includes the steps of: providing aformable sheet of liquid impermeable material; providing an absorbentassembly; providing a sheet of liquid permeable material; providing amold surface; forming the formable sheet on the mold surface to producea moisture barrier defining a basin having a width dimension, a lengthdimension greater than the width dimension, and a volume, the basincomprising a floor having corrugations formed in the floor parallel tothe width dimension; disposing the absorbent assembly in the basin; andbonding the sheet of liquid permeable material to the moisture barrierto sandwich the absorbent assembly therebetween.

Numerous features and advantages of the present invention will appearfrom the following description. In the description, reference is made tothe accompanying drawings which illustrate preferred embodiments of theinvention. Such embodiments do not represent the full scope of theinvention. Reference should therefore be made to the claims herein forinterpreting the full scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a disposable absorbent article accordingto the present invention.

FIG. 2 is a side view of the disposable absorbent article shown in FIG.1.

FIG. 3 is a bottom view of the disposable absorbent article shown inFIG. 1.

FIG. 4 is a longitudinal section view taken generally from the plane ofthe line 4--4 in FIG. 1.

FIG. 5 is a side view of the disposable absorbent article of FIG. 1, butshown in a folded position.

FIG. 6 is a schematic view of a forming mold used to form a moisturebarrier of the disposable absorbent article shown in FIG. 1.

FIGS. 7A through 7E illustrate alternative corrugation patterns whichmay be formed in the moisture barrier of the disposable absorbentarticle.

FIG. 8 is a longitudinal section view of an alternative moisture barrierfor use in a disposable absorbent article according to the presentinvention.

DEFINITIONS

Within the context of this specification, each term or phrase below willinclude the following meaning or meanings:

(a) "bonded" refers to the joining, adhering, connecting, attaching, orthe like, of two elements. Two elements will be considered to be bondedtogether when they are bonded directly to one another or indirectly toone another, such as when each is directly bonded to intermediateelements.

(b) "disposable" includes being disposed of after use, and not intendedto be washed and reused.

(c) "disposed," "disposed on," "disposed with," "disposed at," "disposednear," and variations thereof are intended to mean that one element canbe integral with another element, or that one element can be a separatestructure bonded to or connected to or placed with or placed nearanother element.

(d) "formed" and "formable" describe the condition or property of amaterial to be conformable to a three-dimensional shape and thereaftergenerally retain the three-dimensional shape, for example, through theapplication of heat and pressure to the material in manufacturingprocesses such as thermoforming, vacuum forming, injection molding,mechanical forming, or the like.

(e) "integral" is used to refer to various portions of a single unitaryelement rather than separate structures joined to or connected to orplaced with or placed near one another.

(f) "liquid communication" means that liquid is able to pass between thespecified layers.

(g) "liquid impermeable" when used to describe a layer or laminate meansthat bodily liquids such as urine will not pass through the layer orlaminate under ordinary use conditions in a direction generallyperpendicular to the plane of the layer or laminate at the point ofliquid contact.

(h) "member" when used in the singular can have the dual meaning of asingle element or a plurality of elements.

These terms may be defined with additional language in the remainingportion of the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1-4, a disposable absorbent article 20 formedaccording to the present invention is shown for purposes of illustrationas a feminine incontinence product. The invention may also be embodiedin other types of disposable absorbent articles, such as maleincontinence products, feminine hygiene products, wound dressings, orthe like. The illustrated absorbent article 20 includes a moisturebarrier 22, an absorbent assembly 24 (FIG. 4), a liner 26 and attachmentmeans 28.

The moisture barrier 22 is formed from a flexible, formable materialthat is substantially liquid impermeable. The moisture barrier 22 haslongitudinal end edges 30 and longitudinal side edges 32 extendingbetween the end edges. The side edges 32 are desirably curved so thatthe moisture barrier 22 is hourglass or I-shaped, although the moisturebarrier may also be T-shaped, rectangular, oval, or irregularly-shaped.The moisture barrier 22 has opposite major surfaces designated innersurface 34 and outer surface 36.

As formed, the moisture barrier 22 defines a basin 40 with an integralrim 42 surrounding the basin. The rim 42 forms a generally flat surfacethat is positioned against the wearer during use. The rim 42 candirectly or indirectly contact the wearer, depending on the position ofother materials, such as the liner 26. The rim 42 desirably extendscontinuously around the periphery of the basin 40 and has a generallyuniform width.

The basin 40 of the moisture barrier 22 includes a floor 44 and anintegral peripheral wall 46 surrounding the floor. The basin 40 has alength dimension, a width dimension, and a height dimension.Accordingly, the basin 40 has a volume into which the absorbent assembly24 is positioned. The length dimension of the basin 40 is measuredparallel to the longitudinal axis of the absorbent article 20 and isgenerally greater than the width dimension. Conversely, the widthdimension is measured perpendicular to the longitudinal axis of theabsorbent article 20. The longitudinal axis of the article 20 isdepicted by arrow 47 in FIG. 1. The peripheral wall 46 forms an anglewith the floor 44, thus giving the basin 40 its height dimension andspacing the rim 42 from the floor. In particular embodiments of theinvention, the basin 40 is formed such that the length dimensionmeasures from about 7 to about 30 centimeters, the width dimensionmeasures from about 3 to about 12 centimeters, and the height dimensionmeasures from about 0.2 to about 6 centimeters.

The floor 44 includes first and second longitudinally spaced end regions48 and 49, which are desirably although not necessarily substantiallyflat. An extendable region 50 of the floor 44 is located between andseparates the first and second end regions 48 and 49. The extendableregion 50 of the floor 44 is formed with a plurality of corrugations 52.Each corrugation 52 represents a fold, pleat, set of parallel andalternating ridges and grooves, or the like, in the moisture barrier 22.

The corrugations 52 permit the absorbent article 20 to bend inwardly,for example to conform to the shape of the wearer, without bunching themoisture barrier 22 along the rim 42. In particular, the extendableregion 50 of the floor 44 tends to function as an expandable hinge forthe absorbent article 20, extending in length and bending as theabsorbent article is bent. As shown in FIG. 5, the corrugations 52permit the absorbent article 20 to fold inwardly upon itself, such asfor packaging. This is accomplished without substantially bunching andfolding the moisture barrier 22 along the rim 42, a condition which cangenerate permanent creases in the rim 42 and lead to side leakage fromthe article 20. The corrugations 52 also permit the absorbent article 20to fold inwardly upon itself or against the wearer without substantiallystretching or deforming the floor 44 of the moisture barrier 22. Inparticular, the article 20 can conform to the shape of the wearerwithout substantially reducing the depth of the basin 40 and its abilityto hold the maximum volume of liquid.

The corrugations 52 extend between the side edges 32 of the moisturebarrier 22. The longitudinal axis of the fold, pleat, or set ofalternating ridges and grooves, or the like, which forms eachcorrugation 52 is generally parallel to the width dimension of the basin40, and thus the corrugations 52 are considered to be parallel to thewidth dimension of the basin. The corrugations 52 desirably do notextend into the rim 42 of the moisture barrier 22. This allows the rim42 to remain smooth and fit closely to the wearer. Rather, thecorrugations 52 desirably extend at least partially into the peripheralwall 46 of the basin 40 on each side of the floor 44. The corrugations52 may, for example, begin adjacent the rim 42 and gradually increase indepth approaching the floor 44. The maximum depth of the corrugations 52is desirably maintained across the width of the floor 44.

Depending upon the type of product and its intended use, themanufacturer of the absorbent article 20 may wish to vary the size ofeach corrugation, the frequency of the corrugations, and the distanceover which the corrugations extend, measured along the longitudinal axis47 of the absorbent article. For example, a relatively few number ofrelatively large corrugations 52 may be able to provide the same bendingcharacteristics as a relatively large number of relatively smallcorrugations. Similarly, the frequency or size of the corrugations 52may be reduced if the corrugations extend over a greater longitudinallength of the absorbent article 20. In general regarding the illustratedabsorbent article 20, a greater number of corrugations 52 and/or largercorrugations are required to maintain easy folding capability as thedepth of the product is increased.

The size of the corrugations 52 can vary greatly, such as from about onehalf the thickness of the floor 44 of the formed moisture barrier 22 toabout three-quarters of the depth of the basin 40. In the illustratedabsorbent article 20, for example, the corrugations may have a depth offrom about 0.8 millimeters to about 25 millimeters. Desirably, thecorrugations 52 have a depth of from about 2 to about 6 millimeters. Onesuitable method of determining the depth of a corrugation 52 is toemploy a thickness gauge, such as Custom Scientific thickness gaugeModel CS-55-325 or equivalent gauge which delivers a 0.1 g/cm² loading.The portion of the floor 44 containing the corrugations 52 is removedfrom the article 20 and its thickness measured. A portion of themoisture barrier 22 not containing the corrugations 52, desirably also aportion from the floor 44, is also removed and its thickness measured.The depth of a corrugation is the difference between these twomeasurements.

For the illustrated absorbent article 20, the frequency of thecorrugations 52 may range from 1 to about 96 corrugations every 76millimeters. Desirably, the frequency of the corrugations 52 ranges fromabout 2 to about 5 corrugation every 25 millimeters.

The distance over which the corrugations 52 extend along thelongitudinal axis of the absorbent article 20 depends in part upon thetype of attachment means 28 that are employed. For example, whereadhesive is used on the outer surface 36 of the moisture barrier 22 toattach the absorbent article 20 to a garment, the corrugations 52 mayextend over a longitudinal distance equating to from about 5 to about 75percent of the length of the absorbent article. In the illustratedabsorbent article 20, the corrugations 52 desirably extend alongitudinal distance of from about 20 to about 35 percent of the lengthof the absorbent article. In one particular aspect of the invention, theabsorbent article 20 is approximately 240 millimeters in length and thecorrugations 52 extend over from about 50 to about 75 millimeters of thelength. Alternatively, attachment means 28 other than such garmentattachment adhesive may be employed, in which case the corrugations 52may extend over a longitudinal distance up to the full length of theabsorbent article (not shown).

Formable materials useful for the moisture barrier 22 include variousthermoplastic or thermosetting polymeric resins. The moisture barrier 22may comprise, for example, polyethylene, polypropylene, polyurethane,polyesters, or the like. In one particular embodiment of the presentinvention, the moisture barrier 22 is formed from a thin layer ofclosed-cell, cross-linked polyethylene foam, which may contain a vinylacetate comonomer, commercially available from Voltek Inc. of Lawrence,Mass., USA, under the trade designation Volara. The foam material priorto forming desirably has a density of about 24 to about 96 kg/m³ and athickness of about 1.6 to about 9.5 millimeters. Other thermoplastic orthermosetting polymeric foams and materials, such as thermoformablefilms, nonwovens, or film and nonwoven composites are also suitable foruse in the present invention.

The moisture barrier 22 can be formed from a variety of manufacturingprocesses such as thermoforming, vacuum forming, injection molding,mechanical forming, matched die molding, or the like. In one particularaspect of the invention, the moisture barrier 22 is gas impermeable andformed using a forming mold 60 as shown in FIG. 6. The forming mold 60includes a mold surface 61 having generally flat peripheral portions 62for forming the rim 42 of the moisture barrier 22 and a concave centralportion 63 for forming the basin 40 of the moisture barrier. The concavecentral portion 63 includes a plurality of ridges 64 extendingtransversely across the concave central portion. The ridges 64 aredesirably raised portions of the concave central portion which form thecorrugations 52 in the moisture barrier 22. A plurality of spacedconduits 65 in the forming mold 60 connect the mold surface 61 with avacuum source (not shown).

In one aspect of the invention, a sheet of moisture barrier material 22is heated until the temperature of the moisture barrier material iselevated to its softening point. In one embodiment, the sheet ofmoisture barrier material 22 is a cross-linked polyethylene foam havinga density of about 44 kg/m³ and a thickness of about 2 millimeters, andthe material is heated to a temperature of about 115 to 157 degreesCelsius, particularly about 149 degrees Celsius, for a period of about 5to about 18 seconds, particularly about 8 seconds. Heating temperaturesand times will, of course, vary depending upon the particular moisturebarrier material 22 selected.

The heated sheet of moisture barrier material 22 is positioned againstthe forming mold 60 to form a seal therebetween. This seal allows thematerial to be vacuum drawn onto the mold surface 61. In particularembodiments, the moisture barrier 22 suitably has a formed thickness offrom about, 1.1 to about 2.0 millimeters, and desirably from about 1.6to about 1.8 millimeters. After forming, the sheet of moisture barriermaterial 22 is removed from the forming mold 60, allowed to cool, andcut to the desired dimensions. Alternately, the moisture barrier 22 maybe thermoformed using plug assist, a male mold, both male and femalemolds, drape forming or other suitable techniques (not shown). Othersuitable forming techniques are disclosed in commonly assigned U.S.patent application Ser. No. 08/165,153 filed Dec. 9, 1993, by M. K.Melius et al. for a "Formed Incontinence Article And Method OfManufacture," which is incorporated herein by reference.

One advantage of forming an extendable region 50 in the moisture barrier22 is that the overall moisture barrier as formed can be generally flat.Previously, formed incontinence products had to be formed in a generallycurved shape in the longitudinal direction so that the products wouldfit closely against the body of the wearer. The present moisture barrier22, in contrast, can be formed generally flat, and still conform to thebody of the wearer due to its bending ability. This provides amanufacturing benefit as well because it is easier to process a moisturebarrier 22 that is generally flat than it is to process one that isformed in a longitudinally curved shape, particularly in today'shigh-speed manufacturing environment.

As noted previously, the ridges 64 in the mold surface 61 of the formingmold 60 are desirably raised portions of the concave central portion 63.As a result, the corrugations 52 in the moisture barrier 22 tend toproject toward the inner surface 34 and into the basin 40. The ridges 64may possess a variety of cross-sectional shapes, such as triangular,flared U-shaped, U-shaped, rectangular, or the like. Examples of thecorrugations 52 which result from such variously shaped ridges 64 areillustrated in FIGS. 7A through 7D, which show enlarged longitudinalsection views through portions of the extendable region 50 ofalternative moisture barriers 22. The ridges 64 in the mold surface 61may alternatively comprise depressed portions of the central portion 63(not shown). The corrugations 52 resulting from such depressed ridgesare illustrated in FIG. 7E. Because these corrugations 52 tend toproject toward the outer surface 36 and away from the basin 40, thesecorrugations would tend to be more noticeable to the wearer. Suitableridges 64 may include any combination of the forgoing cross-sectionalshapes.

Another aspect of the invention is illustrated by an alternativemoisture barrier 68 shown in FIG. 8. Components similar to thosepreviously described have been given the same reference numeral. Ingeneral, the moisture barrier 68 desirably possesses sufficientstructural rigidity to form a stand-alone, three-dimensional shell,while at the same time, providing flexibility at some locations toreadily conform to pressures exerted on it during use by a wearer. Notall parts of the moisture barrier 68 are desired to be as flexible,however, and for that reason the moisture barrier 68 of FIG. 8 is formedwith rib means 69.

The rib means 69 enhance resistance to transverse compression of themoisture barrier in the extendable regions 50 of the basin 40. The ribmeans 69 extend parallel to the width dimension of the moisture barrier22, desirably across the full width of the floor 44 and at leastpartially up the peripheral wall 46 on each side of the floor. In theillustrated embodiment, the rib means 69 are located on eitherlongitudinal end of the extendable region 50, adjacent the corrugations52. The rib means 69 could alternatively be located in other regions ofthe floor, such as between corrugations 52, provided the rib means 69 donot impede bending of the extendable region 50. The moisture barrier 68may contain a plurality of rib means 69, and desirably comprises fromabout 2 to about 10 rib means.

The rib means 69 may comprise enhanced thickness portions of the floor44 as illustrated. Such enhanced thickness portions may be formedintegral with the remaining portions of the floor 44 or separatelyprovided and attached to the floor. In one embodiment, the rib means 69are formed in part by strips, ribbons, rods, fibers, filaments, fabrics,foams, or the like, made from thermoformable or non-thermoformablematerials such as polymers, polyethylene, polypropylene, polyesters, orthe like. Alternatively, the rib means 69 may comprise heavily densifiedportions of the floor 44 which have an enhanced resistance to transversecompression of the moisture barrier 68, compared to other portions ofthe floor. Still alternatively, the rib means 69 may be formed from asingle foam sheet that is pleated a plurality of times and thereafterthermoformed.

One suitable method for measuring resistance to transverse compressionof the moisture barrier 22 is a Half-Width Compression Test which usesan Instron Model 5213 actuator available from Instron EngineeringCorporation, Canton, Mass. The Instron tester includes a 50 kilogramload cell (compression) and is operated with a crosshead speed of 100millimeters per minute. The procedure uses two half cylinders mounded onthe Instron tester so that the curved surfaces of the half cylindersface one another and are movable toward one another. The half cylindersmay be formed by longitudinally separating a can having a diameter of15.24 centimeters into equal halves. After being conditioned in a roomwhich is 21±1 degree Celsius and 50±2 percent relative humidity for aperiod of two hours, the sample to be tested is positioned on the lowerhalf cylinder such that a peripheral wall 46 that is parallel to thelongitudinal axis 47 of the sample is in contact with the curved surfaceof the half cylinder. The rim 42 of the sample is positioned against anend of the half cylinder so that the basin 40 can rest against thecurved surface of the lower half cylinder. The crosshead is lowereduntil the surface of the upper half cylinder, which is mounted on thecrosshead, just touches the basin 40 of the sample. Thus, thelongitudinal sides of the basin 40 are positioned between the halfcylinders, while the rim 42 is located adjacent the ends of the halfcylinders. A plate is positioned against the bodyside surface of thesample and hand held against the sample so that the absorbent assembly24 of the sample does not bow outward from between the half cylinders asthe half cylinders are moved together. The crosshead is actuated so thatthe distance between the upper and lower half cylinders is reduced by 50percent, and the peak load registered during that movement is noted.

The absorbent assembly 24 (FIG. 2) is positioned in the basin 40 anddisposed on the inner surface 34 of the moisture barrier 22. Theabsorbent assembly 24 is desirably formed to be sufficiently flexible toreadily conform to the contour of the inner surface 34 and be capable offolding inward to the same extent as the moisture barrier 22. Theabsorbent assembly 24 is desirably moveable relative to the innersurface 34 of the moisture barrier 22 to allow for bending of theabsorbent article 20.

The absorbent assembly 24 comprises a liquid storage layer 80 formed ofa material adapted to absorb and retain urine, and optionally, anacquisition layer 82 (FIGS. 1 and 4). The absorbent assembly 24 isgenerally configured according to the amount of liquid intended to beabsorbed, and the absorbent rate and capacity of the assemblycomponents. In particular embodiments, the storage layer 80 suitably hasa capacity of urine of from about 25 to 400 grams, particularly about220 grams. The urine capacity of the storage layer 80 is its saturatedretention capacity, which is a measure of the total absorbent capacityof an absorbent garment, material or structure after being subjected to35.1 g/cm² pressure for five minutes.

The liquid storage layer 80 may comprise various absorbent materials,such as an air-formed batt of cellulosic fibers (i.e., wood pulp fluff)or a coform material composed of a mixture of cellulosic fibers andsynthetic polymer fibers. The liquid storage layer 80 may also includecompounds to increase its absorbency, such as 0-100 weight percent oforganic or inorganic high-absorbency materials, which are typicallycapable of absorbing at least about 15 and desirably more than 25 timestheir weight in water. Suitable high-absorbency materials are describedin U.S. Pat. Nos. 4,699,823 issued Oct. 13, 1987, to Kellenberger et al.and 5,147,343 issued Sep. 15, 1992, to Kellenberger, which areincorporated herein by reference. High-absorbency materials areavailable from various commercial vendors, such as Dow Chemical Company,Hoechst Celanese Corporation, and Allied Colloids, Inc.

The storage layer 80 may also include a tissue wrap layer to helpmaintain the integrity of the fibrous core. This tissue wrap typicallycomprises a hydrophilic cellulosic material, such as creped wadding or ahigh wet-strength tissue.

The acquisition layer 82 is superposed on top of and in liquidcommunication with the storage layer 80. Dots or lines of adhesives,ultrasonic bonds or other suitable means may be employed to bond theacquisition layer 82 to the storage layer 80. The acquisition layer 82may be generally the same size and shape as the storage layer 80,however it is desired that the acquisition layer be shorter than thestorage layer, as illustrated in FIGS. 1 and 4.

The acquisition layer 82 can be or can contain any suitable material formanaging, transporting, accommodating, permitting, or directing rapidand/or sudden flow of urine therethrough and into contact with thestorage layer 80. The acquisition layer 82 desirably functions to drawliquid from the liner 26 and then permit desorption by the storage layer80. Included among suitable components for acquisition layer 82 arefibers such as polypropylene, polyethylene, polyester, blends thereof,or the like. One suitable material for the acquisition layer 82 is alatex bonded rayon web, which is available from Sackner Products ofGrand Rapids, Mich. under the trade designation SN-92. An acquisitionlayer 82 of this type desirably has a thickness of about 6.35millimeters and a basis weight of about 120 grams per square meter.Other suitable materials are disclosed in U.S. Pat. No. 4,798,603 issuedJan. 17, 1989, to Meyer et al., which is incorporated herein byreference.

The liner 26, which is formed of a substantially liquid permeablematerial, is positioned to sandwich the absorbent assembly 24 betweenthe liner and the moisture barrier 22. Desirably, the liner 26 isdirectly bonded to the moisture barrier 22 along the rim 42, as shown inFIG. 4. The moisture barrier 22 and liner 26 may be bonded togetherusing adhesives, thermal bonds, ultrasonic bonds or other suitablemeans. The liner 26 may also be bonded directly to the absorbentassembly 24 using thermal bonds, adhesives, ultrasonic bonds or othersuitable means. In an alternate embodiment, the liner 26 is positioneddirectly over the storage layer 80 and the acquisition layer 82 isbonded to the surface of the liner that is remote from the storage layer(not shown).

The liner 26 may be any soft, flexible, porous sheet which passes fluidstherethrough. The liner 26 may comprise, for example, a nonwoven web orsheet of wet strength tissue paper, a spunbonded, meltblown orbonded-carded web composed of synthetic polymer filaments, such aspolypropylene, polyethylene, polyesters or the like, or a web of naturalpolymer filaments such as rayon or cotton. The liner 26 has a pore sizethat readily allows the passage therethrough of liquids, such as urineand other body exudates. The liner 26 may be selectively embossed orperforated with discrete slits or holes extending therethrough, such asan apertured film material. Optionally, the web or sheet may be treatedwith a surfactant to aid in liquid transfer. One suitable surfactant isidentified as Triton X-102 and available from Rohm and Haas Corporationof Philadelphia, Pa., USA. Examples of suitable liner materials includea wettable spunbonded polypropylene web having a basis weight of 24grams per square meter, and a wettable bonded carded web ofpolyethylene/polypropylene side-by-side conjugate fibers having a basisweight of 20 grams per square meter.

The attachment means 28 (FIGS. 2-5) of the absorbent article 20 includetwo strips of garment attachment adhesive 88 secured to the outersurface 36 of the moisture barrier 22. Additionally, removable peelstrips 89 cover the attachment adhesive 88 until use and preventcontaminates from contacting the attachment adhesive. In an alternativeembodiment, a single peel strip could be used to cover the two spacedstrips of attachment adhesive 88 (not shown). Still alternatively, othersuitable attachment means such as belts, straps, bodyside adhesives,attachment tapes, mechanical fasteners, or the like, could be used tohold the article in place.

In the illustrated embodiment, the strips of attachment adhesive 88 aredisposed on the floor 44 of the basin 40, with one adhesive striplocated in each of the first and second end regions 48 and 49.Desirably, the attachment adhesive strips 88 are disposed on the floor44 solely in these end regions 48 and 49 and not located in theextendable region 50, so that the attachment adhesive 88 does notinterfere with extension and retraction of the corrugations 52. Inparticular embodiments wherein the end regions 48 and 49 also includecorrugations (not shown), smaller adhesive strips or other means ofattachment can be used.

In use, the wearer removes the peel strips 89 and attaches theattachment adhesive 88 to the inside surface of an undergarment. Theattachment adhesive 88 allows the absorbent article 20 to remain inposition to receive discharged liquids. While securing the absorbentarticle 20 and while in use, the article easily bends to fit theundergarment and fit against the body of the wearer. In embodimentsemploying the lateral rib means 64 (FIG. 8), particular regions of theabsorbent article 20 have enhanced resistance to transverse compression.

EXAMPLE

An absorbent article 20 of the type illustrated in FIG. 1 wasconstructed from the following materials. The moisture barrier 22 was across-linked polyethylene foam containing a vinyl acetate comonomer,available from Voltek Inc. of Lawrence, Mass., USA, under the tradedesignation Volare. The foam material had a density of 64 kg/m³ and athickness of 1.5 millimeters. The liner 26 was apolyethylene/polypropylene side-by-side conjugate spunbonded materialhaving a basis weight of 20.4 grams per square meter. The storage layer80 consisted of two separate layers, each a substantially uniformair-laid mixture of wood pulp fluff and high-absorbency. One layer hadan hourglass shape and contained wood pulp fluff at 300 grams per squaremeter and high-absorbency material at 135 grams per square meter. Thesecond layer had a rectangular shape and contained wood pulp fluff at590 grams per square meter and high-absorbency material at 630 grams persquare meter. The two layers were wrapped in tissue and jointlycompressed. The acquisition layer was a latex-bonded carded web of rayonfibers material having a basis weight of 120 grams per square meter,available from Sacknet Products of Grand Rapids, Mich. under the tradedesignation SN-92. The garment attachment adhesive was apressure-sensitive adhesive and the peel strip was a coated paper.

The moisture barrier material 22 was cut into a 38.1 centimeter squaresheet. The peripheral 2.54 centimeters of the sheet of moisture barriermaterial 22 was clamped into a metal frame. The frame and sheet ofmoisture barrier material were inserted into an oven at a temperature of270 to 300 degrees Fahrenheit (132°-149° Celsius) for 5 to 7 seconds.The frame and sheet of moisture barrier material were removed from theoven, and the sheet was then drawn by a vacuum into a forming mold likethat shown in FIG. 6. The formed moisture barrier material was cooled bya fan for 10 seconds and removed from the metal frame.

Peripheral portions of the moisture barrier material were then cut byhand and removed, leaving the basin 40, the surrounding integral rim 42,and some excess moisture barrier material. The storage layer andacquisition layer were cut to fit in the basin and disposed therein. Theliner was heat sealed to the rim 42. The liner and moisture barrier werecut to produce a 1.6 centimeter rim 42 extending around the basin 40.Two strips of garment attachment adhesive 88 were applied to the outersurface 36 of the moisture barrier 22 and covered with peel strips 89.

The foregoing detailed description has been for the purpose ofillustration. Thus, a number of modifications and changes may be madewithout departing from the spirit and scope of the present invention.For instance, alternative or optional features described as part of oneembodiment can be used to yield another embodiment. Therefore, theinvention should not be limited by the specific embodiments described,but only by the claims.

We claim:
 1. A method of making an absorbent article, comprising thesteps of:providing a formable sheet of liquid impermeable material;providing an absorbent assembly; providing a sheet of liquid permeablematerial; providing a mold surface; forming the formable sheet on themold surface to produce a moisture barrier defining a basin and anintegral rim surrounding the basin, the basin having a width dimension,a length dimension greater than the width dimension, and a volume, thebasin comprising a floor having corrugations formed in the floorparallel to the width dimension, the corrugations beginning adjacent therim and increasing in depth in the direction of the floor; disposing theabsorbent assembly in the basin; and bonding the sheet of liquidpermeable material to the moisture barrier to sandwich the absorbentassembly therebetween.
 2. The method of claim 1, wherein the step offorming the formable sheet comprises heating the formable sheet to asoftening point of the formable sheet.
 3. The method of claim 1, whereinthe mold surface defines a concave central portion with generally flatperipheral portions surrounding the concave central portion, the concavecentral portion including a plurality of ridges extending transverselyacross the concave central portion.
 4. The method of claim 1, furthercomprising the step of forming the floor with rib means which extendparallel to the width dimension for providing enhanced resistance totransverse compression of the moisture barrier.
 5. The method of claim4, wherein the rib means comprise from about 2 to about 10 enhancedthickness sections which extend over the full width dimension of thefloor.
 6. The method of claim 5, wherein the enhanced thickness sectionscomprise separate members bonded to the moisture barrier.
 7. The methodof claim 5, wherein the enhanced thickness sections comprise integral,relatively thicker portions of the floor.
 8. The method of claim 1,wherein the floor has first and second longitudinally spaced end regionsand an extendable region between the end regions, the corrugations arelocated in the extendable region, and the method further comprises thestep of inwardly folding the absorbent article about an axis parallel tothe width dimension and located between the end regions such that theextendable region is elongated.
 9. The method of claim 1, wherein thecorrugations have a depth of from about 0.8 millimeters to about 25millimeters.
 10. The method of claim 9, wherein the corrugations have adepth of from about 2 to about 6 millimeters.
 11. The method of claim 1,wherein the maximum depth of the corrugations is maintained across thewidth of the floor.
 12. The method of claim 1, wherein the corrugationsoccur in a frequency of from 1 to about 96 corrugations every 76millimeters.
 13. The method of claim 12, wherein the corrugations occurin a frequency of from about 2 to about 5 corrugations every 25millimeters.
 14. The method of claim 1, wherein the corrugations extendover a longitudinal distance of from about 5 to about 75 percent of thelength of the absorbent article.
 15. The method of claim 14, wherein thecorrugations extend over a longitudinal distance of from about 20 toabout 35 percent of the length of the absorbent article.
 16. A method ofmaking an absorbent article, comprising the steps of:providing aformable sheet of liquid impermeable material; providing an absorbentassembly; providing a sheet of liquid permeable material; providing amold surface; forming the formable sheet on the mold surface to producea moisture barrier defining a basin and an integral rim surrounding thebasin, the basin having a width dimension, a length dimension greaterthan the width dimension, and a volume, the basin comprising a floorhaving first and second longitudinally spaced end regions and anextendable region between the end regions, the extendable region havingcorrugations formed therein parallel to the width dimension, thecorrugations beginning adjacent the rim and increasing in depth in thedirection of the floor; disposing the absorbent assembly in the basin;bonding the sheet of liquid permeable material to the moisture barrierto sandwich the absorbent assembly therebetween; and disposing apressure-sensitive adhesive on the floor solely in the end regions. 17.The method of claim 16, further comprising the step of forming the floorwith rib means which extend parallel to the width dimension forproviding enhanced resistance to transverse compression of the moisturebarrier.